One of the most vexing problems facing Iowans is how to confront the extensive social and environmental costs that result from the factory farming of cattle, hogs and poultry, coupled with the production of corn and soybeans. These industries all create pollutants that compromise the state’s air and water quality.

While Iowa farmers defend their right to farm, others are increasingly concerned that the external costs of these agricultural practices outweigh their benefits. When it comes to corn and soybeans, these costs are so extensive that the city of Des Moines, which depends on local rivers for the city’s drinking water, installed the largest nitrate removal facility in the world to deal with three upstream countries with severe agricultural runoff issues.

To understand how so much nitrate ended up in Iowa’s drinking water, check out this short film:

Scientists have long understood that plants like corn and soybeans grow best in soils with the proper complement of sixteen nutrients. Of these, nitrogen, phosphorus, and potassium—a divine trinity collectively known by their atomic symbols, NPK—are the most important.

For plants to absorb nitrogen (N), farmers have always added composts, crop waste, and animal manure to the soil. These increased SOIL FERTILITY and resulted in better harvests. Until the 20th century, many Japanese even used human feces as fertilizer. A respectful dinner guest—after ingesting his host’s valuable nutrients—would often deposit NIGHT SOIL in grateful recompense before departing.

But farmers weren’t nearly as efficient as a German scientist named Fritz Haber. In the early 1900s his Haber Process resulted in the production of ammonium nitrate, a chemical that fixes nitrogen in the soil. Its primary ingredient? Natural gas. Ammonium nitrate dramatically improved crop yields, and as people learned in World War I, also made very effective weapons.

When the war ended, chemical companies that had assembled laboratories and ramped up production to manufacture large quantities of ammonium nitrate–based explosives now turned their attention back to agriculture.

Soon farmers who were once guided by the lunar calendar, who carried their knowledge from one season—and one generation—to the next, received instructions printed on the side of a fertilizer bag.

Today, half the world’s food production depends on a fertilizer whose main ingredient is natural gas. These chemical fertilizers and herbicides are the foundation of industrial agriculture, and a major factor in the public’s perception that food costs have lowered over the last one hundred years. But cheap food comes with a price: chemically produced nitrogen can be carried away in agricultural runoff that pollutes our soils and leaches nitrates into our drinking water, our waterways, and our oceans. These EXTERNAL COSTS make the real price of our industrialized foods higher—and more dangerous—than you think.

Nitrate removal at Des Moines Water Works uses an ion exchange process similar to those found in home water softeners, with a sodium chloride-coated resin material used to capture and remove nitrate ions while releasing chloride ions into the water.

Nitrates in drinking water, for example, can pose serious health risks, which is why in 2015, the Des Moines Water Works, Iowa’s largest water utility, filed a lawsuit in federal court against upstream drainage districts in three counties, citing that for years fertilizer runoff on agricultural land had leached into local waterways and polluted the drinking water of nearly 500,000 Des Moines residents. The case was a test. Could a federal law, the Clean Water Act of 1972 and its provisions for safe drinking water (SDWA), be used at the local level to compel farmers to change their farming practices? Would the Environmental Protection Agency join the fight?



AFTER LEARNING ABOUT the impact of industrial agriculture on their state’s water quality, three teachers at Iowa’s Ames High School (Mike Todd, Joe Brekke and Chad Zmolek) inspired their students to embark on a year-long class project using THE LEXICON OF SUSTAINABILITY’S project-based learning curriculum, Project Localize. It helped the students research the state’s rich agricultural history, interview farmers, water quality experts, and environmental attorneys, then translate the ideas of these innovative thinkers into information artworks that graphically depict the agricultural practices responsible for Iowa’s poor water quality as well as the numerous solutions which could be put in place to make farmers better land and water stewards.

As a testament to the quality of their investigation, the following sections share the work of students from Ames High School: